With the recent increase in the number of people enjoying baseball, a so-called screen baseball system has emerged, which overcomes the limitations of playing baseball in a wide baseball stadium and allows people to enjoy playing a virtual baseball game even in a small indoor space while experiencing virtual reality.
Typically, a screen baseball system is installed in an indoor space and has a batting area with a space of a predetermined size in which a user can bat and a screen capable of displaying a virtual baseball field. When a pitching machine installed on the back of the screen pitches a ball toward the batting area, a user who is ready to hit the ball in the batting area hits the ball pitched by the pitching machine. At this time, a sensing device senses the movement of the pitched ball and the movement of the ball hit by the user. Subsequently, based on the result of sensing, whether the pitched ball is a strike or a ball is determined, and an image simulating the trajectory of the hit ball is realized on the screen.
In connection with the sensing device, a conventional screen baseball system is configured to have a structure in which a plurality of optical sensor devices, each of which includes a plurality of light-emitting sensors and a plurality of light-receiving sensors, is installed in a path along which a pitched ball or a hit ball moves such that, when the ball passes by the optical sensor devices, the light-receiving sensors receives the light emitted by the light-emitting sensors and reflected by the ball, whereby each of the optical sensor devices acquires information about the coordinates of the ball in order to calculate the speed, direction, and the like of the pitched ball or the hit ball based thereon.
In the case in which a user hits a ball with a bat, whether the user swung or hit the ball is sensed using an additional sensor device.
The above-described technical content is disclosed in a plurality of related art documents, such as Korean Patent Application No. 10-2015-0041844, Korean Patent Application No. 10-2015-0041861, Korean Patent Application No. 10-2014-0054105, U.S. Pat. No. 5,443,260, and Japanese Registered Patent No. 4743763.
In the case in which a sensor device based on an optical sensor is used, as described above, it is necessary to provide a considerable number of light-emitting sensors and light-receiving sensors. As a result, costs related to the sensor device are considerably increased. In addition, there is a strong possibility of the sensor device being damaged or malfunctioning, whereby it is very difficult to maintain and repair the sensor device. Nevertheless, accurate analysis of a ball motion is limited, whereby accuracy in simulation of the ball motion is very low.
An image-processing-type sensing device that is capable of acquiring an image of the motion of a pitched ball or a hit ball, analyzing the acquired image, and calculating various kinds of information showing how the ball moves in a baseball practice apparatus has been proposed.
The image-processing-type sensing device is advantageous in that a plurality of frames of an image is processed in order to accurately analyze the motion of a pitched ball or a hit ball but is disadvantageous in that it is not possible to perform effective and rapid processing, since the number of images is very large and the amount of data generated as the result of processing the images is also very large.